<template>
  <view>
    <!-- 使用自定义的搜索组件 -->
    <my-search @click="gotoSearch"></my-search>
    
    <view class="scroll-view-container">
      <scroll-view class="left-scroll-view" scroll-y="true" :style="{height: wh + 'px'}">
        <block v-for="(item, i) in cateList" :key="item.cat_id">
          <view :class="['left-scroll-view-item', i === active ? 'active' : '']" @click="activeChanged(i)">{{item.cat_name}}</view>
        </block>
      </scroll-view>
      <scroll-view scroll-y="true" :style="{height: wh + 'px'}" :scroll-top="scrollTop">
        <view class="cate-lv2" v-for="(item2, i2) in cateLevel2" :key="i2">
          <view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
         <!-- 动态渲染三级分类的列表数据 -->
          <view class="cate-lv3-list">
            <!-- 三级分类 Item 项 -->
            <view class="cate-lv3-item" v-for="(item3, i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
              <image :src="item3.cat_icon"></image><!-- 文本 -->
              <text>{{item3.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  import badgeMix from '@/mixins/tabbar-badge.js'
  export default {
    mixins: [badgeMix],
    data() {
      return {
        // 窗口的可用高度 = 屏幕高度 - navigationBar高度 - tabbar 高度
        wh: 0,
        cateList: [],
        active: 0,
        cateLevel2: [],
        scrollTop: 0
      };
    },
    onLoad(){
      const sysInfo = uni.getSystemInfoSync()
      console.log(sysInfo)
      this.wh = sysInfo.windowHeight - 50;
      this.getCateList();
    },
    methods: {
      async getCateList(){
        try{
          const res = await uni.$http.get('/api/public/v1/categories');
          if(res.meta.status !== 200) return uni.$showMsg();
          
          this.cateList = res.message;
          this.cateLevel2 = res.message[0].children;
        }catch(e){
          //TODO handle the exception
          uni.$showMsg();
        }
      },
      activeChanged(i){
        this.active = i;
        this.cateLevel2 = this.cateList[i].children;
        
        this.scrollTop = this.scrollTop === 0 ? 1 : 0;
      },
      
      gotoGoodsList({cat_id}){
        uni.navigateTo({
          url: `/subpkg/goods_list/goods_list?cid=${cat_id}`
        })
      },
      
      gotoSearch(){
        uni.navigateTo({
          url: '/subpkg/search/search'
        })
      }
    }
  }
</script>

<style lang="scss">
.scroll-view-container{
  display: flex;
  .left-scroll-view{
    width: 120px;
  }
  .left-scroll-view-item{
    line-height: 60px;
    background-color: #f7f7f7;
    text-align: center;
    font-size: 12px;
    // 激活项的样式
    &.active {
      background-color: #ffffff;
      position: relative;

      // 渲染激活项左侧的红色指示边线
      &::before {
        content: ' ';
        display: block;
        width: 3px;
        height: 30px;
        background-color: #c00000;
        position: absolute;
        left: 0;
        top: 50%;
        transform: translateY(-50%);
      }
    }
  }
  .cate-lv2-title {
    font-size: 12px;
    font-weight: bold;
    text-align: center;
    padding: 15px 0;
  }
  .cate-lv3-list {
    display: flex;
    flex-wrap: wrap;
    .cate-lv3-item {
      width: 33.33%;
      margin-bottom: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      image {
        width: 60px;
        height: 60px;
      }
      text {
        font-size: 12px;
      }
    }
  }
}
</style>
